The present invention relates to a wing for an aircraft. The wing comprises a main wing, a slat and a connection assembly for movably connecting the slat to the main wing, such that the slat can be moved between a retracted position, for cruise flight, and at least one extended position, preferably two or more extended positions, for take-off and landing.
The connection assembly comprises an elongate, preferably rod-shaped, first link element and a second link element. The first link element has a first link end and an opposite second link end. The first link end is rotatably, in particular pivotably, mounted to the slat via a first joint. The second link end is rotatably, in particular pivotably, mounted to the main wing via a second joint. The second link element has a first element end and an opposite second element end. The first element end is rotatably, in particular pivotably, mounted to the slat via a third joint that is spaced apart from the first joint. The second element end is rotatably, in particular pivotably, mounted to the main wing via a fourth joint that is spaced apart from the second joint.
There are wings known in the art employing a slat track to movably mount the slat to the main wing. The slat is usually connected to one end of the slat track in a fixed manner, while the slat track is mounted to the main wing in such a way that it is movable in a direction along the longitudinal axis of the slat track. In such a way, the movement of the slat is defined alone by the movement of the slat track along a predetermined path in the direction of its longitudinal axis. Such a slat track and the corresponding movement path of the slat track require considerable room in the leading edge portion of the main wing, so that a front spar of the main wing usually has to be penetrated by the slat track when the slat track is in the retracted position, which in turn requires a complex construction.
Alternative wings are known in the art which do not employ a slat track, but instead employ a linkage kinematics. From U.S. Pat. No. 1,780,838 and from WO2008/135266A1 a four bar linkage is known, wherein two link elements are coupled to the slat with their first ends and are coupled to the main wing with their opposite second ends. Both link elements are coupled to the slat and to the main wing in a way spaced apart from one another and rotatable about axes of rotation that extend in the wing span direction. Such an arrangement requires the link elements, the joints and the actuators to be formed with high strength in order to resist the air-loads on the slat. From U.S. Pat. No. 1,780,838 it is also known that the axes of rotation of the four bar linkage might extend in the wing thickness direction instead of in the wing span direction. In such a way, the slat carries out a lateral movement but no curved movement along the curvature of the wing profile.